Since the mid-1800s, ships have used bilge keels to mitigate roll motions due to waves. The use of bilge keels to minimize ship roll motion was first suggested by Froude. Historically, bilge keels have featured flat plate designs, and later also included discontinuous fin or wedge type designs along the ship's length. FIG. 1 shows a conventional flat bilge keel 10. Conventional bilge keels are used to mitigate and dampen small to moderate roll motions. As ships have increasingly expanded operations into more severe environments, conventional bilge keels have been less effective.
Older conventional bilge keels were typically constructed from a metal plate and filled with wood, and then riveted to the hull at the desired location. Modern bilge keels are constructed entirely from metal plates, and filled with foam-based materials. Due to considerations related to docking at piers and to operations in shallow waters, bilge keels are typically constrained to not protrude beyond the beam or the keel of the ship. For these reasons, the size of bilge keels is limited, and has not been increased substantially, which would provide more effectiveness. Thus, it is desired to have bilge keels that provide increased stability without increasing the width. The prior art does not teach bilge keels with curved surfaces and shaped edges for providing stability and energy dissipation optimization.